Some Natural Phenomena – Multiple Choice Questions

Q1. When an ebonite rod is rubbed with fur

  • Electrons move from the fur to the ebonite rod
  • Electrons move from the ebonite rod to the fur
  • Protons move from the fur to the ebonite rod
  • Protons move from the ebonite rod to the fur

Solution

When an ebonite rod is rubbed with fur, it acquires negative charge which means it gains electrons.

Q2. Power of an earthquake is measured on the ___________ scale. An increase in 1 point on this scale indicates a force of an earthquake that is ______ times greater than the strength of the previous number.

  • Richter, five
  • Richter, ten
  • Seismic, ten
  • Seismic, hundred

Solution

Power of an earthquake is measured on the Richter scale. An increase in 1 point on the Richter scale indicates a force of an earthquake that is ten times greater than the strength of the previous number.

Q3. Consider the following statements:
I.   Lightning occurs between the Earth and the clouds
II.  Lightning occurs between the same clouds
III. Lightning occurs due to the discharge between charged clouds and the Earth
Among the given statements,

  • Only statement I is correct
  • Only statement II is correct
  • Statements I and III are correct
  • Statements II and III are correct

Solution

During lightning, negative and positive charges of the lower and upper parts of different clouds conduct each other. The negatively charged lower part of the cloud conducts with the positively charged Earth. Lightning occurs due to a discharge between different clouds. It does not occur due to a discharge between the upper and lower parts of the same cloud. Hence, only statement II is incorrect.

Q4. Seismograph is an instrument that records the

  • Heights of tides
  • Duration of a solar eclipse
  • Intensity of a thunderstorm
  •  Vibrations of the surface of the Earth

Solution

Seismograph is an instrument that records the vibrations of the surface of the Earth.

Q5. By how much does the destructive energy of an earthquake of magnitude 7 compare to an earthquake of magnitude 5?

  • 10
  • 100
  • 1000
  • 10000

Solution

For a magnitude change of 2 the destructive energy is 1000 times greater.

Q6. In order to protect against electrical shocks, _________is done in domestic circuits. It is a process of charge transfer from the metal case of an electrical appliance to the ground. This transfer of charges involves ____________.

  • Earthing, induction
  • Earthing, conduction
  • Insulation, conduction
  • Insulation, induction

Solution

In order to protect against electrical shocks, earthing is done in domestic circuits. It is a process of charge transfer from the metal case of an electrical appliance to the ground. This transfer of charges involves conduction.

Q7. Two bodies A and B (A bigger than B) are rubbed together. Which of the following statement is true

  • A and B get equal and opposite charges
  • A and B get equal and similar charges
  • A gets more charge than B but of opposite kind
  • A gets less charge than B but of opposite kind

Solution

A and B get equal and opposite charges in accordance with the principle of conservation of charges.

Q8. An electroscope is a device that is used to

  • Detect whether an object is a conductor or not
  • Measure the amount of charge on an object
  • Detect whether an object is charged or not
  • Check magnetic properties of a substance

Solution

An electroscope is a device that is used to detect whether an object is charged or not.

Q9. Which of the following objects cannot be charged by physical connection?

  • Iron rod
  • Graphite lead
  • Aluminium foil
  • Cardboard sheet

Solution

The process of charging in which an object is charged by bringing it in contact with a charged object is called charging by conduction. For charging by conduction to occur, both the objects should be made up of conducting materials. Cardboard sheets are made up of wood, which is a non-conducting material. Hence, a cardboard sheet cannot be charged by physical connection or by contact.

Q10. When a charged object is brought near an uncharged object, it gets attracted. This process involves charging by

  • Conduction
  • Induction
  • Friction
  • Electrification

Solution

When a charged object is brought near an uncharged object, it gets attracted. This process involves charging by induction.

Q11. What are the weak zones along the boundaries of the plate where earthquakes are more likely to occur known as?

  • Seismic zones
  • Richter zones
  • Tsunami zones
  • Lightening zones

Solution

The weak zones along the boundaries of the plate where earthquakes are more likely to occur are known as seismic zones.

Q12. ____________ occur when the surface of the Earth shakes due to tremors on the Earth. 

  • Earthquakes
  • Volcanoes
  • Cyclones
  • Thunder and lightning

Solution

Earthquakes occur when the surface of the Earth shakes due to tremors on the Earth.

Q13. Which of the following cannot be charged easily by friction?

  • An inflated balloon
  • A plastic scale
  • A woollen cloth
  • A copper rod

Solution

Only non-conducting materials can be easily charged by friction. Copper is a highly conducting material. Therefore, a copper rod cannot be charged easily by friction.

Q14. Two uncharged bodies when rubbed together get charged. This is because of

  • Conduction
  • Induction
  • Friction
  • show of the above

Solution

Two uncharged bodies when rubbed together get charged. This is because of friction.

Q15. When a comb rubbed on hair is brought near bits of paper, it attracts them, because

  • The comb and the paper bits get oppositely charged
  • The comb and the paper bits get similarly charged
  • The paper bits are very light
  • The paper can fly in air

Solution

When a comb rubbed on hair is brought near bits of paper, it attracts them because the comb and the paper bits get oppositely charged.

Q16. Static electricity is referred to that electricity which

  • Always flows from positively charged bodies to negatively charged bodies
  • Always flows from negatively charged bodies to positively charged bodies
  • Does not flow
  • Continuously flows from positively charged bodies to negatively charged bodies and vice-versa

Solution

Static electricity is referred to that electricity which does not flow.

Q17. An earthquake is said to be destructive if the reading on the _________ scale is ________ than 7.

  • Decibel, less
  • Decibel, more
  • Richter, less
  • Richter, more

Solution

An earthquake is said to be destructive if the reading on the Richter scale is more than 7.

Q18. When a charged object is brought near an uncharged object, it gets ___________. This process involves charging by ___________.

  • Attracted, conduction
  • Attracted, induction
  • Repelled, induction
  • Repelled, conduction

Solution

Charging by induction explains how an uncharged object gets charged when a charged object is brought near it. When a charged object is brought near an uncharged object, the uncharged object becomes charged with the opposite charge. Since unlike charges attract each other, these two objects attract each other.

Q19. Lightning contains a tremendous amount of

  • Chemical energy
  • Nuclear energy
  • Heat energy
  • Electrical energy

Solution

Lightning contains a tremendous amount of electrical energy. It is actually a great electric spark in the sky.

Q20. The outermost layer of the Earth consists of movable pieces called ______, and the boundaries of these form _______ zones in the Earth’s crust, which are also called seismic zones.

  • Mantle, strong
  • Mantle, weak
  • Plates, strong
  • Plates, weak

Solution

The outermost layer of the Earth consists of movable pieces called plates, and the boundaries of these form weak zones in the Earth’s crust, which are also called seismic zones.

Q21. Rahul wants to purchase a house in a country. He has to choose a place among four countries. The seismographic readings of four countries are given below. Among the given countries, which country should he chosen for his purchase?

  • https://images.topperlearning.com/topper/tinymce/imagemanager/files/physics/cbse_phy_8/20761_Seismographicreading_OptA.png
  • https://images.topperlearning.com/topper/tinymce/imagemanager/files/physics/cbse_phy_8/20761_Seismographicreading_OptB.png
  • https://images.topperlearning.com/topper/tinymce/imagemanager/files/physics/cbse_phy_8/20761_Seismographicreading_OptC.png
  • https://images.topperlearning.com/topper/tinymce/imagemanager/files/physics/cbse_phy_8/20761_Seismographicreading_OptD.png

Solution

Rahul must take the occurrence of earthquakes in a country under consideration before purchasing the house. The height of vibrations of the seismographic waves determines the intensity of earthquakes. The greater the height, the greater will be the intensity and vice-versa. Also, the number of waves counts for the number of earthquakes. It can be observed from the given seismographic records that earthquakes have occurred with minimum intensity in country 3. Hence, Rahul should purchase a house in country 3.

Q22. A plastic comb is rubbed against dry hair gently. What is the effect on both the plastic comb and dry hair?

  • Both get charged
  • Both get discharged
  • Plastic comb gets charged, but dry hair does not
  • Dry hair gets charged, but plastic comb does not

Solution

When a plastic comb is rubbed against dry hair vigorously, then there is a transfer of charge taking place between the two. As a result, both objects become charged. While one becomes positively charged, the other becomes negatively charged.This is called charging by friction.

Q23. If the divergence of the leaves of an electroscope is more, then the given body is positively charged because

  • The charge on the leaves is more on touching the positively charged body
  • There is no charge on the body
  • The charge on the leaves is less on touching the negatively charged body
  • There is a fluctuation in the charge of the leaves on touching the positively charged body.

Solution

If the divergence of the leaves of the electroscope is more, then the given body is positively charged because the charge on the leaves is more on touching the positively charged body.

Q24. Run a comb through dry hair and bring it near some small bits of paper. What will you notice?

  • The pieces of paper are attracted to the comb
  • The pieces of paper are repelled by the comb
  • Some bits of paper are attracted while others are repelled
  • show of the above.

Solution

If a comb is run through dry hair, an electrostatic force is produced by virtue of which the comb acquires an electrical charge. If the comb is now brought near small bits of paper, it will attract the paper pieces.

Q25. Consider the following two statements regarding four objects P, Q, R, and S.
I. Object P attracts object Q.
II. Object R repels object S.
Which of the following statements can be true?

  • All the objects have the same kind of charge
  • Objects P and Q do not have any charge
  • At most two objects are charged
  • Object Q is uncharged

Solution

According to statement I, object P attracts object Q. This implies that either the objects have opposite charges or one of the objects is charged and the other is uncharged. This is possible because of charging by induction. When a charged object is brought near an uncharged object, the uncharged object becomes charged with the opposite charge. Since unlike charges attract each other, these two objects attract each other. Hence, either object P or object Q or both are charged. Hence, there can be a possibility that object Q is uncharged.

Q26. What are the waves produced by tremors on the surface of the earth called? Which instrument is used to record them?

  • Seismic waves, seismograph
  • Fault waves, seismograph
  • Seismic waves, Richter scale
  • Fault waves, Richter scale

Solution

Seismic waves are the waves produced by tremors on the surface of the earth. The seismograph is an instrument used to record them.

Q27. When a glass rod is rubbed with a piece of silk cloth the rod and the cloth

  • Acquire positive charge
  • Becomes positively and negatively charged, respectively
  • Acquire negative charge
  • Becomes negatively and positively charged, respectively

Solution

When an object is charged by rubbing it against another object, the two objects get oppositely charged. By convention, it is considered that the charged acquired by the glass rod is positive and charged acquired by the cloth is negative. Therefore, the rod becomes positively charged and the cloth becomes negatively charged.

Q28. Which of the following statements are correct?

1. An earthquake is a sudden shaking or trembling of the earth.

2. The earth is balanced on the horn of a bull and when the bull shifts it to the other horn, an earthquake takes place.

3. Earthquakes occur all the time, all over the earth.

4. Major earthquakes can cause immense damage.

  • 1, 2, 3 only
  • 2, 3, 4 only
  • 1, 2, 4 only
  • 1, 3, 4 only

Solution

An earthquake is a sudden shaking or trembling of the earth. Earthquakes occur all the time, all over the earth. Major earthquakes can cause immense damage.

Q29. Three statements regarding the precautions to be taken during lightning strikes are written below.
I) Avoid bathing during a lightning strike.
II) Avoid the use of electrical appliances.
III) Avoid sitting inside a car.
Among the given statements,

  • Only I is correct
  • Only III is correct
  • Both I and II are correct
  • Both II and III are correct

Solution

Lightning can strike telephone cords, during a thunderstorm. Any contact with these should be avoided. Bathing should be avoided during thunderstorms to avoid contact with running water. A closed shelter like a car is infact safe during lightning.

Q30. Which of the following phenomena does not involve electric charges?

  • Rubbed comb attracts paper pieces
  • Lightning occurs in a rainy environment
  • A loose plug in the socket produces sparks
  • Crane attracts iron pieces from a junkyard

Solution

In junkyards, large electromagnets are used for moving metallic junks such as scraped vehicles. This is a magnetic effect because the electromagnet of the crane attracts metallic junk to move them from one place to another. The working of the crane in a junkyard does not have any involvement of electric charges.